大花杓兰根际土壤真菌及兰科菌根真菌多样性分析

Diversity of Rhizospheric Fungi and Potential Orchid Mycorrhizas on Cypripedium macranthum Estimated by Clone Library Technique

【目的】从分子水平上对兰科杓兰属大花杓兰根际土壤真菌群落组成及潜在兰科菌根真菌进行初步研究。【方法】采用克隆文库技术对大花杓兰根际土壤真菌的ITS片段进行PCR扩增、克隆测序及BLAST分析。【结果】共获得96个真菌克隆,其中44个克隆鉴定为未知真菌,52个真菌克隆基于97%的序列相似性被划分为24个操作分类单元(Operational Taxonomic Unit, OTU),属于5门6纲11目16科15属。被孢霉属Mortierella为大花杓兰根际土壤的主要真菌类群。综合兰科植物菌根真菌的研究报道,对24个OUTs进一步分析,发现4个OTUs为潜在的兰科菌根真菌,分别属于角担菌科Ceratobasidiaceae的丝核菌属Rhizoctonia(OTU1)和角担菌属Ceratobasidium(OTU2)及胶膜菌科Tulasnellaceae(OTU3和OTU4)。【结论】根际土壤真菌及潜在兰科菌根真菌类群的构成及多样性研究,对从土壤中分离筛选有效的大花杓兰菌根真菌及其野生种群的迁地保育均具有重要意义。

【Objective】The diversity of fungi and potential orchid mycorrhizas in Cypripedium macranthum rhizospheric soil collected from Baihuashan Natural Reserve in Beijing was preliminarily revealed at the molecular level.【Method】Clone library technique was used to analyze the composition of fungal community.【Result】96 rhizospheric fungi were cloned, of which 44 rhizospheric fungi cloned were unknown, and 52 rhizospheric fungi based on 97 % sequence similarity levels were divided into the total of 24 operational taxonomic units(OTUs), which belonged to 5 phyla, 6 calss, 11 order, 16 family and 15 genera. Among these fungi identified, Mortierella was dominant genera in rhizosphere soil of C. macranthum. According to reports on orchid mycorrhizal fungi, it was speculated that 4 OUTs might be potential mycorrhizal fungi, which were Rhizoctonia, Ceratobasidium, and Tulasnellaceae, respectively.【Conclusion】The preliminary analysis on the composition of rhizosphere soil fungi and potential orchid mycorrhizas was of great significance for isolating and screening of certain mycorrhizal fungi that were associated with C. macranthum seed germination. Meanwhile, the research results were also beneficial for ex-situ conservation of wild C. macranthum.